The QUANTITATIVE IMAGE ANALYSIS AND SINGLE-CELL TECHNOLOGY CORE will provide state-of-the-art assessment of viral burden, replication, and status of T-cell populations in vivo in lymphoid and other tissues by in situ hybridization techniques, with or without amplification, immunohistochemical, and double-label methods. These techniques, in conjunction with quantitative image analysis, will be employed to identify the number and types of infected cells, the nature of infection (latent, abortive or productive), and the relationship of infection to changes in the numbers of CD4+ T-cells in different subsets during infection and in response to treatment. Dr. Haase of the University of Minnesota will be the director of the core. Dr. Haase and Dr. Cavert, Ms. Zupancic, Ms. Gebhard, Ms. Evans and Mr. Wietgrefe, his staff at the University of Minnesota, will be responsible for overseeing, in detail, the tissue specimen handling, fixation and processing to ensure the integrity of the RNA and DNA, transcript-specific detection probe construction and labeling and in situ hybridization. In addition to providing the scientific resources to perform these laboratory studies, the computer resources and technical expertise to rigorously analyze the in situ data will be provided. The goal of the core is to provide access to: (1) in situ hybridization with and without amplification to detect and characterize viral RNA and viral DNA; (2) in situ hybridization and immunohistochemistry to determine the types of infected cells; (3) in situ hybridization and quantitative image analysis to determine the number of cases of HIV-1 DNA in various cellular compartments; and (4) in situ hybridization and immunohistochemistry and quantitative image analysis to assess changes in CD4+ T cell populations in tissues. The quantitative image analysis and single-cell technology core will facilitate access to state-of-the-art technology, lower cost, and most important, enhance interactions between investigators that lead to new scientific projects.